#include<stdio.h>
int main()
{
	int i = 0;
	int arr[10] = {};
	int sum = 0;
	for (i = 0; i < 10; i++)
	{
		scanf_s("%d", &arr[i]);
			sum += arr[i];
	}
	double average = sum / 10.0;
	printf("%lf", average);
	return 0;
}